(a) Field of the Invention
The present invention relates to a system and a method of manufacturing a liquid crystal display.
(b) Description of Related Art
A liquid crystal display (LCD) includes a liquid crystal (LC) panel assembly including a pair of panels provided with field-generating electrodes and a LC layer interposed therebetween. The field-generating electrodes are supplied with voltages to generate electric field for rearranging LC molecules in the LC layer, thereby controlling light passing through the LC layer. The panel assembly further includes a plurality of signal lines for transmitting the voltages to the field-generating electrodes.
The LCD further includes a plurality of driving circuits connected to the signals lines for supplying signals thereto. The driving circuits are formed of integrated circuit (IC) chips. The driving IC chip is mounted on a flexible printed circuit (FPC) film including an insulating film made of polyimide and provided with a plurality of conductive leads printed thereon. The FPC film mounting the driving IC chip called tape carrier package (TCP) is bonded by tape automated bonding (TAB) such that the IC chip is electrically connected to the signal lines on the panel assembly through the leads on the TCP.
The leads of the TCP include a plurality of input and output leads respectively connected to input and output terminals of the IC chip mounted on the TCP, and the signal lines of the panel assembly include a plurality of pads disposed near edges of the panel assembly. The output leads of the TCP are physically and electrically connected to the pads of the panel assembly, while the input leads of the TCP are connected by soldering to a printed circuit board for supplying several signals to the driving IC.
The bonding of the output leads of the TCP and the pads of the panel assembly is performed by interposing an anisotropic conductive film (ACF) therebetween, which are made of thermosetting or thermo thermoplastic resin containing a plurality of conductive particles dispersed therein, and by thermocompression with a heating tool made of metal or ceramics.
Since the heating tool generates high temperature for reliable bonding, it may be deformed by the high temperature to decrease its flatness and its life. The high temperature may also cause defects in a joint of the heating tool and in the driving ICs and the panel assembly.
In particular, it is easy for the flatness of a large heating tool for a large LCD to be decreased. The lower flatness of the heating tool may fail to uniformly pressing the conductive particles of the ACF, thereby causing defect in connection between the TCP and the panel assembly.